An accumulator disclosed DE 101 13 415 A1 is in the form of a hydropneumatic accumulator. A flexible separating element is in an accumulator housing formed by the end piece of a pipe. The element surrounds a support body having fluid passages. The support body, at least in individual sections, has a nonround cross-sectional shape. The separating element is anchored on the accumulator housing with the formation of a seal such that, on the outside and inside of the separating element, receiving spaces are formed which are separate from one another. A centrally located through bore forms a passage leading to the inner receiving space of the accumulator for a storage medium. There is a gas valve for filling the outside gas space. The known accumulator can be used for energy storage, for example, in conjunction with vehicle suspension system or as pulsation dampers. This known solution is especially well suited for damping of pressure peaks in hydraulic or other fluid-engineering systems. The known solution leaves much to be desired for use as an accumulator for storage media in the form of chemically corrosive fluids, such as a urea-water solution.
Another accumulator disclosed in DE 38 10 509 C2 comprises a main body of a tank with an outer pipe of cylindrical shape on whose one end there is a side plate and on whose other end there is a cover. At least one inlet opening and one outlet opening are formed on the outer pipe. A bladder or diaphragm subdivides the interior of the main body of the tank into a gas chamber and a liquid chamber, with an opening of the bladder being sealed tight by the cover. An insert is arranged to project into the bladder for the purpose of reducing the volume of the gas chamber. The insert is formed from a base part, a middle part, and a head part, with the head part being kept in contact with the bottom of the diaphragm. This arrangement permits preventing damage of the diaphragm by repeated contraction. In the contracted state, the bladder or diaphragm adjoins the insert.
Accumulators of this type are widely used in different sizes and structural configurations to receive and discharge variable volumes of pertinent fluids under the operating pressure of a fluid system that is connected on the fluid side. The bladder, which is under a preloading pressure of the working gas, forms a pressure cushion on its gas side. The operational reliability of the accumulator depends primarily on the accumulator bladder typically formed of a plastic material, especially butyl, which bladder is exposed not only to mechanical stresses in operation, but also needs to be resistant to chemically corrosive storage fluids, if possible. As has been shown, in conjunction with corrosive fluids such as urea-water solutions, so far to ensuring a problem-free service life of sufficient length for continuous operation, for example, over 20,000 hours, has not been possible.
“Urea injection” is being increasingly used in automotive engineering to reduce the nitrogen oxide (NOx) emissions by injection into the exhaust gas flow. In this type of application, achieving a long service life without problems in continuous operation is especially important.